From Ernest Hemingway's "Death in the Afternoon" chapter two..
"..Domingo Hernandorena, a short, thick-ankled, graceless Basque with a pale face who looked nervous and incompletely fed in a cheap rented suit...."
"Hernandorena could not control the nervousness of his feet. He wanted to stand quietly and play the bull with the cape with a slow movement of his arms, but when he tried to stand still as the bull charged his feet jumped away in short, nervous jerks. His feet were obviously not under his personal control and his effort to be statuesque while his feet jittered him away out of danger was very funny to the crowd. It was funny to them because many of them knew that was how their own feet would behave if they saw the horns coming toward them, and as always, they resented any one else being in there in the ring, making money, who had the same physical defects which barred them, the spectators, from that supposedly highly paid way of making a living."
We see their failings on the field as an affront to our since of self, I could wrap up that tackle, I could read that defense, I could kick that ball, and then reality sets in and we realize that no we could not. So rather than admit that, we boo to punish the player for being too much like us.
I really have no problem booing professional athletes who fail to give at least their best effort.
I did not understand Green Bay fans booing Brett Farve, after all it was the Packers who divorced him for a younger QB.
I do not understand booing a collage player who is doing his best, but failing due to a lack of experience or simply being physically out matched. Booing in this instance is arrogance at its worst.